SUCTION GAS FOR MOTORS.
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By Major David J. Smith, M.Inst.A.E.
INOTICE in the issue of THE COMMERCIAL MOTOR for 30th May a communication from Mr. F. E. Raymond regarding the use of suction-gas as a motor fuel. From this letter it would stem that he is not very familiar with the latest developments in-saction-gas, even as applied to stationary engines. To take one remark in his letter to the effect that the stationary gas engine has scavenging strokes. Is not Mr. Raymond a-ware that Crossley and other firstclass makes of suction-gas engines are throttle controlled, the throttle being actuated by the governor ? Therefore, the engine takes gas in varying quantities according to the power required, but never "cuts out;" as was the, practice on old-type -gas engines, which had, therefore, scavenging .strokes, such as Mr: Raymond speaks of. Strangely enough, I am not aware' that these engines suffer from pre-ignition, necessitating constant removal of carbon from the combustion. chamber. I have in mind many suction gas plants, which have been running on munition work practically night and day for many months without requiring such constant cleaning as Mr. Raymond mentions. I should advise him to -communicate with MesSts: Crossleys, Tangyes, and other well-known firms, who will no doubt allow him to inspect. such plant S, ivhich haVe been So running, and. also to disabuse himself of his conclusions.
" Mr.. Raymond also mentions the difficulties which would be met with every time the vehicle stopped to load and unload. If the stop is likely to be short, nothing .would be gained by stopping the engine, as the cost difuel is -practically nil -and, -therefore,sexcept.for :wear and tear, there is no reason -why the engine should not be run for a stop up to; say, half an hour: If .the vehicle had to stop. for a longer period, it would Undoubtedly, as he states, take a fewminutes to .re-start it, but I do not think, in view of the-many other advantages, attached to suction gas,.
that this would be.a, serious matter. • •
As for -any unpleasantness experienced in the Vicinity of the vehicle while the .producer was being fanned un, thisis. quite imaginary, as a very small volume of gas, projected intothe op-en air, would be absolutely unnoticeable. • ..:_ ...' . Mr. Raymond aka). seenis to i be bituminous Coal-with anthracite coal.'I do not think it would he possible to use a bituminous coal suction-gas producer on a Vehicle ., in fact, the use of this fuel, even in a
. stationary plant, is attended with difficulty. With anthracite, however, there is praotically DO tar given
off, and, with any decent form of scrubber, no carbon Ands its way into the engine. This does not occur even on a stationary plant, and there is no reason why it -should occur when the gas is used on a motor engine.
Mr. Raymond then deals with the question of weight of a suction-gas plant and, in this, seems to base his remarks entirely on stationary producer de sign. There is no earthly reason why the producer for motor swork should be lined with 4 ins, of fire-brick and then 2 -ins, of sand ; neither is there any reason why the door at the bottom of the furnace or the vaporizer should be made of cast-iron. Also, Mr: Raymond does not seem cognizant of the quality of the present coal-gas which is being sup plied, and on which many motor vehicles are running successfully. Much of this gas is certainly no better than gas given by a good producer using the hest anthracite, and, therefore, the remarks regarding the loss of power would not come in.
Mr. Raymond evidently is not aware of theexperiments which were alluded to in the article Hi THE COMMERCIAL MOTOR in the issue of 16th May. These
experiments were successful, but a-s at the time they were being made the price of petrol was somewhere in the neighbourhood of 7d. a gallon, it was not likely that anyone would be troubled with any other form of fuel, as even if the whole -of the petrol bill could have been saved it would not in any ease have amounted to,very much. _
As one who successfully mastered this problem about six years. ago, I am able to state that thiswas the main reason -why suction gas was not taken seriously. At the present time, things might be different, as even if there is no shortage of petrol, the Price has undoubtedly advanced, and this would' make the matter worth considering.
.1 would, however, before leaving the matter, advise Mr. Raymond to make himself cognizant -of what has
been done on stationary plants withsuction gas, as
obviously his experience must have been gained a very long time ago. Mast of the difficulties which 'he
puts forward have been Met and overcome,'and, if at the present time there is really a. demand for suction gas on motor vehicles, there is a system in existence which will meet that demand. .